/*
 * receiver2.c 
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include <unistd.h>

int port = 6789;
void main()
{
    socklen_t sin_len;
    char message[256];
    int socket_descriptor;
    struct sockaddr_in sin;
    int bind_rc, close_rc;
    ssize_t recv_rc;
    printf("Waiting for data from sender\n");

    /*
     * Initialize socke address structure for Internet Protocols
     */

    bzero(&sin, sizeof(sin)); /* empty data structure */
    sin.sin_family = AF_INET;
    sin.sin_addr.s_addr = htonl(INADDR_ANY);
    sin.sin_port = htons(port);
    sin_len = sizeof(sin);

    /*
     * Create a UDP socket
     * and bind it to the port
     */

    socket_descriptor = socket(AF_INET, SOCK_DGRAM, 0);

    if (socket_descriptor == -1) {
        perror("socket call ailed");
        exit(errno);
    }

    bind_rc = bind(socket_descriptor, (struct sockaddr *) &sin, sin_len);
    if (bind_rc == -1) {
        perror("bind call failed");
        exit(errno);
    }
   
    /*
     * Loop forever (or until a termination message is received)
     * Receive data through the socket and process it.The processing 
     * in this progremm is really simple -- printing.
     */

    while (1) {
        recv_rc = recvfrom(socket_descriptor, message, sizeof(message), 0, (struct sockaddr *)&sin, &sin_len);
        if (recv_rc == -1) {
            perror("recvfrom call failed");
            exit(errno);
        }

        printf("Response from server: %s\n", message);
        if (strncmp(message, "stop", 4) == 0) {
            printf("Sender has told me to end the connection\n");
            break;
        }

    }

    /*
     * Most people don't bother to check the return code 
     * returned by the colse function
     */

    close_rc = close(socket_descriptor);
    if (close_rc == -1) {
        perror("close call failed");
        exit(errno);
    }

    exit(0);
}
